Effectively engaging learners in an online learning environment is a crucial component of instructional design that contributes to improving performance. Gamification, a contemporary instructional strategy, seeks to integrate game elements such as leaderboards into non-game contexts with the aim of increasing learner engagement and performance. This quasi-experimental study explores the impact of integrating leaderboards as a gamification element into formative assessment on learner achievement and engagement in an engineering course. Conducted over eight weeks in the Mechatronics Technology Department of a public university in Türkiye, the study involved 159 s-year engineering students. Using a pretest-posttest control group design, the intervention included a pre-test in the first week, six weeks of instruction and formative online assessment, and a post-test in the final week. Analyzing the data using descriptive and inferential statistics, the results of the study show a positive correlation between the incorporation of a leaderboard as a gamification element into formative assessment procedures within an online platform and improved learner achievement and engagement. However, it is noted that gamification may not sustain learners' long-term attention. Therefore, instructors are advised to carefully consider time and retention concerns when designing or adopting gamified learning opportunities.